Fuel heating system for internalcombustion engines



June 11, 1946. DUGAS 2,401,862

FUEL HEATING SYSTEM FOR INTERNAL-COMBUSTION ENGINES Filed Api-il 5, 1945 gr p ll JJDu as i am; t... ,11, 1946 UNITED sT 'rss PATENT OFFICE FUEL HEATING SYSTEM FOR INTERNAL-- COMBUSTION ENGINES Joseph J. Dugas, New Orleans, La... assignor to Higgins Industries, Inc., New Orleans. corporation of Louisiana La., a

Application April 5, 1945, Serial No. 586,796

Claims. (01. 123-1226) This invention relates to internal combustion engines.

The general object of the invention is to adapt a carburetor to use heavy fuel. The carburetor may be of ordinary construction, having a float chamber supplying fuel to'a nozzle, and a riser from the nozzle taking vaporized fuel to the intake manifold. The invention places a coil of tubing in the float chamber and a similar coil in the riser. These coils are connected in series.

Hot'combustion gases are drawn through these coils for heating them, the combustion gases being generated in a small external heater. The

idea in heating the float chamber isto reduce the viscosity of the heavy fuel so that it will atomize in the nozzle. The purpose of heating the riser is to vaporize the atomized fuel. Since it takes higher temperature to vaporize than it Q does to reduce vsicosity, the hot gases are drawn serially from the heater, first through the riser coil, and thenlthrough the float chamber coil.

Another object of the invention is to heat the fuel prior to the starting of the engine, as well as while it is running. Consequently, means are provided for sucking the combustion productsfrom the external heater through the coils, before the engine starts, this means being a vacuum pump. The vacuum in the engine is relied upon after the engine starts. The intake manifold of the engine and the vacuum pump are therefore connected by a tube, and a branch from this tube is connected to the coil in the float chamber.

Still another object of the invention is the provision of a control system whereby the engine cannot be started or attempted to ,be. started until the fuel is preheated, the control means being as follows. In the preliminary heating period,

the starting circuit and the ignition circuit are I rendered inoperative. When the heater has run long enough to produce the desired temperature in the riser, a thermostat closes a gap, which renders the the starting and ignition circuits potontially operative, then upon pressing the starting button, the engine is turned over and ignition takes place.

Still another object: of the invention is to provide means whereby the vacuum pump will not be supplanted by the intake suction of the'engine as a means for circulating the heating medium immediately upon the turning over of. the engine by the starter, but not until the engine has started under its own power. Therefore, some function of the engine, such as the development of oil pressure in the lubrication system, i utilized for stopping the vacuum pump.

Another object of the invention resides in the construction and arrangement of the external heater, which in its preferred embodiment drawsv heavy fuel from the float chamber. of the car- .buretor, and which is therefore provided with electrical heating means energized concurrently with the starting of the vacuum pump for heating the cold fuel in advance of its introduction to .the combustion chamber of the heater.

.Other objects of the invention will appear as the following description of a preferred and practical embodiment thereof proceeds.

In-the drawing which accompanies and forms a part of the following specification, the sole figure isv a longitudinalsectional view, largely diagrammatic, showing an internal combustion engine with the carburetor connected thereto, and embodying the features of the present invention, including the electrical control.

Referring now in detail to the drawing, the

' numeral i represents an internal combustion engine having the intake manifold 2, intake valve 3, and a conduit 4, forming part of the pressure lubrication system.

The intake manifold 2 is connected to the upper end of a riser 5, the lower end of which is connected to the carburetor 6. The riser is provided with a jacket I.

mg I! and has an incandescent tip i'l exposed within the combustion tube It. The latter has an air inlet l8, communicating with atmosphere. The nozzle I5 is surrounded by an electric heater l9, which is in parallel circuit with the igniter i8, so that both the igniter and heater are simultaneously energized.

A heating coil 20 isarranged longitudinally within the-riser 5, having its lower end connected to the combustion tube i 4, and its upper end opening into the upper end of the jacket 1. The lower end of the jacket is connected by a tube 21, which preferably passes through the casing i3 and is connected to one end of a heating coil 22, located 'float chamber.

' within the fl'oat chamber 8. Thus, the heater I2 is the anterior element of serially connected members including in sequence coil 20, jacket 1 and coil 22, and is therefore subject to suction imposed upon thecoil 22, by which suction air and fuel are drawn into the combustion tube it.

The end of the coil 22 is connected to a. tube 23, which has a vacuum pump 24 connected to one end, the other end communicating with the intake' manifold 2 of the engine. A check valve 25 in said tube is open while the vacuum pump 24 is running, and at this time a -check valve-26 adiacent the intake manifold2 is closed. When the engine is running and the vacuum pump has stopped, the check valve 26 is open and the check valve 25 closed. When either the vacuum pump 24 or the en e has control of the suction with-. in the tube 23, air and fuel are drawn into the some engine functionlwhich comes into being 4 the vacuum pump motor circuit the action of the vacuum pump responsive to when the engine has started under its own power.

In the disclosed embodiment of'the invention, the pressure of the lubricating oil built up through operation of the engine is utilized for this purpose. A normally open diaphragm switch 38 has its diaphragm chamber in communication with the lubricating oil conduit 4. When the pressure in this conduit has built up, the diaphragm combustion tube- M of the heater, ignited by the igniter I6 and circulated serially through the coil 6, Jacket 1 of the riser and the coil 22 in the float chamber.

The operation of the invention is controlled in 'the following manner. Prior to starting the engine, the ignition switch 21 is closed. This closes a circuit from the battery 28, through the wire 29, through the motor 30 of the vacuum pump, to

ground. A circuit is likewise closed through the wire 3i, igniter i6 and electric heater IS to ground. This causes cold, heavy fuel to be picked up by the pick-up tube It, which is heated and atomized at the nozzle 15, mixed with air drawn in through the inlet It of the heater, ignited by the incandescent tip I! ofthe igniter, and circulated through the coil 6 and jacket 1 of the riser and through the coil 22 in the float chamber of the carburetor. Since the coil 6 is the first of the serially connected heat dissipating elements, the combustion products are hotter at this pointthan in the coil 22. This is as it should be. since as has been suggested, it requires more heat to vaporize the atomized fuel particles than to reduce the viscosity of the liquid fuel in the A little heat may be picked up by the passage of the tube 2| through the casing i2 of the heater. In the event that the combustion gases should still retain an appreciable amount of heat after passingthrough the coil 22, a cooler 82 may be intercalated in the tube 23 between the coil 22 and the vacuum pump.

At the time the vacuum pump is started, it is desirable to make it impossible to try to start the engine on the cold heavy fuel. Therefore, a relay circuit 33 is provided, which is normally open at a thermostatically controlled switch. 84, the thermostat 35 of which is-responsive to the temperature ofthe riser. When the temperature of the riser has risen sufficiently to produce a vaporized fuel, the thermostat 35 closes the circuit through the wire 33, energizing the relay 42, which pulls down the solenoid switch 43, makswitch closes, establishing a circuit through the wire 39, which energizes a solenoid 40, opening a normally closed switch 4| in the vacuum pump motor circuit and stopping the vacuum .pump.

When the vacuumpump ceases to operate, the.

check valve- 25 closes, so that the suction of the engine intake is imposed solely upon the coil 22. While I have in the above description disclosed what I believe to be a preferred and practical embodiment of the invention, it will be understood to those skilled in the art that the specific details of construction and the arrangement 'of parts and circuits, as disclosed, are by way of example and not to be construed as limiting the scope ofthe invention.

What I claim as my invention is:

1. In combinatioman internal combustion engine, a conduit for conducting a flow of heated medium in heat exchanging'relation to fuel supplied to said engine, alternatively operable vacuum means connected to said conduit for induc-.

ing a flow of heated medium therethrough, one means being the engine, the others; vacuum pump operated independently of the engine prior to starting of the engine.

2. In combination, an internal combustion engine, a conduit for conducting a flow of heated medium in heat exchanging relation to fuel supplied to said engine, alternatively operable vacuum means connected to said conduit for induc- I changing relation to the fuel i said supply coning'independently of the engine connected to duit, said second conduit having branches. one connected to said intake, a vacuum pump operatthe other, said intake and said vacuum pump alternatively functioning to induce a flow of heated medium through said second conduit,

ing the starter switch 36 potentially active, and

at the same time, energizing a pilot light 31, which when lit indicates that the fuel mixture is in condition topermit starting of the engine. The starting switch 36 is then closed and a current passes through the starter 44, turning over the engine.

When the starier switch as is closed, the vacuum pump is not immediately cut out, for the degree of vacuum created by the mere turning over' of. the engine by the starter may not be sufllcient to open the check valve 28 and pick up the circulation of the heating medium without interruption. Therefore, it is preferred to open means for operating said vacuum pump before the engine starts, means responsive. to a funtion of the enginewhile running for discontinu-v ing the operation of the vacuum pump, and means responsive to the temperature of the fuel within said first mentioned conduit to prevent the engine from being started until a predetermined high temperature of said fuel has been attained.

. 4." In combination, an internal combustion engine including a fuel intake, and fuel conditioning means connected to said intake from which A fuel is supplied to the engine through suction of the intake, said conditioning means includinga fuel reservoir. a generator -'of hot combustion products, heat exchanging means connected thereto for bringing said combustion products and discontinue independently of said engine. a connection from said heat exchanging means to said engine intake and to said vacuum pump, means for operating the vacuum pump before the engine starts and means responsive to a function of the engine when running for stopping the vacuum pump, whereby the engine and vacuum pump constitute alternative means for drawing fuel from said reservoir to said generator and combustion products from said generator through said heat exchanging means.

5. The combination as claimed in claim 4, in cluding means responsive to predetermined high temperature of said conditioning means created by said heat exchanging means, to. prevent the engine being started until high temperature has been attained.

6. In combination, an internal combustion engine including an intake, a carburetor including a vaporizing chamber supplying fuel to said intake, said carburetor having a float chamber, a heater for generating hot combustion products having a fuel nozzle driving liquid .fuel from said float chamber, having an air inlet and an igniter, a heat exchanging conduit from said heater positioned in heat exchanging relation to said vaporizing chamber, said conduit being connected to the engine intake, a vacuum pump driven independently of the engine connected to said conduit, said intake and vacuum pump functioning alternatively to impose suction upon the combuschamber, a heat exchanging conduit connected to said generator and serially associated with said riser and said float chamber, a vacuum pump driven independently ofv the engine, a connection from said heat exchanging conduit to said engine intake and to said vacuum pump, means for operating said vacuum pump before the engine starts, and means responsive to a function of the engine when running for stopping the vacuum pump whereby the engine and vacuum pump constitute alternative means for drawing fuel from said float chamber to said generator and combustion products from said generator through said heat exchanging conduit.

8. The combination as claimed in claim 7, said means responsive to a function of th engine for stopping the vacuum pump comprising an element responsive to build-up of lubricating oil pressure incident to the running of the engine.

9. In combination, an internal combustion-engine including a fuel intake, a carburetor including a float chamber and an atomizing nozzle, means forming a vaporizing chamber connecting said carburetor to said intake in which the atomizing fuel is vaporized, a heat exchanging conduit for bringing a heated medium into heat exheated medium through said heat exchanging conduit.

10. The combination as claimed in claim 9, including a vacuum pump connected to the said other end of said heat exchanging conduit operating independently of the engine, for drawing heated medium through said heat exchanging conduit before the engine starts, and means responsive to a function of the engine when running for stopping said vacuum pump.

JOSEPH J. DUGAS. 

